Batteries which are made up of a plurality of individual cells are subject to degradation of performance when one or more of these cells has a lower capacity with respect to the other cells. Such a cell will exhibit reduced voltage output with respect to the remaining cells. When the battery is connected to a load, the combined voltage of the cells connected in series with the problem cell can cause reverse polarity in the problem cell. This can cause that cell to overheat, or may induce adverse reactions within the cell which can cause it to become hazardous.
Modern hermetically sealed lithium batteries, for example, are constructed with cells having vented casings which will open up once sufficient pressure builds within the cell. The venting of these cells, however, can release dangerous or noxious gases into the environment. Should these vents fail to operate properly, a lithium battery can explode.
It is, therefore, an object of this invention to provide a means of sequentially monitoring each of the cells comprising a battery in order to detect a problem cell before venting occurs.
It is a further object of the invention to cause the battery to be disconnected from the load, upon detection of a problem cell.
It is still a further object of the invention to cause all of the cells to discharge safely, upon detection of a problem cell, allowing for safe disposal of the battery.